On Wed, 2023-09-20 at 13:36 +0200, Markus Armbruster wrote:
> Nina Schoetterl-Glausch <[email protected]> writes:
>
> > From: Pierre Morel <[email protected]>
> >
> > The modification of the CPU attributes are done through a monitor
> > command.
> >
> > It allows to move the core inside the topology tree to optimize
> > the cache usage in the case the host's hypervisor previously
> > moved the CPU.
> >
> > The same command allows to modify the CPU attributes modifiers
> > like polarization entitlement and the dedicated attribute to notify
> > the guest if the host admin modified scheduling or dedication of a vCPU.
> >
> > With this knowledge the guest has the possibility to optimize the
> > usage of the vCPUs.
> >
> > The command has a feature unstable for the moment.
> >
> > Signed-off-by: Pierre Morel <[email protected]>
> > Reviewed-by: Nina Schoetterl-Glausch <[email protected]>
> > Co-developed-by: Nina Schoetterl-Glausch <[email protected]>
> > Signed-off-by: Nina Schoetterl-Glausch <[email protected]>
> > ---
> > qapi/machine-target.json | 37 +++++++++++
> > hw/s390x/cpu-topology.c | 132 +++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 169 insertions(+)
> >
> > diff --git a/qapi/machine-target.json b/qapi/machine-target.json
> > index 0d45a590ce..e47a252bd9 100644
> > --- a/qapi/machine-target.json
> > +++ b/qapi/machine-target.json
[...]
> > +# Modifies the topology by moving the CPU inside the topology
> > +# tree or by changing a modifier attribute of a CPU.
> > +# Default value for optional parameter is the current value
> > +# used by the CPU.
>
> So, anything absent will not be changed. Maybe that's a clearer way to
> put it. What do you think?
Yes.
>
> > +#
> > +# Returns: Nothing on success, the reason on failure.
> > +#
> > +# Since: 8.2
> > +##
> > +{ 'command': 'set-cpu-topology',
> > + 'data': {
> > + 'core-id': 'uint16',
> > + '*socket-id': 'uint16',
> > + '*book-id': 'uint16',
> > + '*drawer-id': 'uint16',
>
> CpuInstanceProperties uses 'int' for these. Any particular reason for
> the difference?
unsigned -> no need to check if >0
16bit is also the width the hardware uses for these values on s390.
> > + '*entitlement': 'CpuS390Entitlement',
> > + '*dedicated': 'bool'
> > + },
> > + 'features': [ 'unstable' ],
> > + 'if': { 'all': [ 'TARGET_S390X' , 'CONFIG_KVM' ] }
> > +}
>
> [...]
>
